This invention relates to newly identified polynucleotides, polypeptides encoded by such polynucleotides, the use of such polynucleotides and polypeptides, as well as the production of such polynucleotides and polypeptides. More particularly, the polypeptide of the present invention is a prostatic growth factor which is sometimes hereinafter referred to as xe2x80x9cPGFxe2x80x9d.
This invention relates to a polynucleotide and polypeptide molecules which are structurally and functionally related to TGF-xcex2. The transforming growth factor-beta family of peptide growth factors includes five members, termed TGF-xcex21 through TGF-xcex25, all of which form homo-dimers of approximately 25 kd. The TGF-xcex2 family belongs to a larger, extended super family of peptide signaling molecules that includes the Muellerian inhibiting substance (Cate, R. L. et al., Cell, 45:685-698 (1986)), decapentaplegic (Padgett, R. W. et al., Nature, 325:81-84 (1987)), bone morphogenic factors (Wozney, J. M. et al., Science, 242:1528-1534 (1988)), vg1 (Weeks, D. L., and Melton, D. A., Cell, 51:861-867 (1987)), activins (Vale, W. et al., Nature, 321:776-779 (1986)), and inhibins (Mason, A. J. et al., Nature, 318:659-663 (1985)). These factors are similar to TGF-xcex2 in overall structure, but share only approximately 25% amino acid identity with the TGF-xcex2 proteins and with each other. All of these molecules are thought to play an important roles in modulating growth, development and differentiation. The protein of the present invention, PGF, retains the seven cysteine residues conserved in the C-terminal, active domain of TGF-xcex2.
TGF-xcex2 was originally described as a factor that induced normal rat kidney fibroblasts to proliferate in soft agar in the presence of epidermal growth factor (Roberts, A. B. et al., PNAS USA, 78:5339-5343 (1981)). TGF-xcex2 has subsequently been shown to exert a number of different effects in a variety of cells. For example, TGF-xcex2 can inhibit the differentiation of certain cells of mesodermal origin (Florini, J. R. et al., J.Biol.Chem., 261:1659-16513 (1986)), induced the differentiation of others (Seyedine, S. M. et al., PNAS USA, 82:2267-2271 (1985)), and potently inhibit proliferation of various types of epithelial cells, (Tucker, R. F., Science, 226:705-707 (1984)). This last activity has lead to the speculation that one important physiologic role for TGF-xcex2 is to maintain the repressed growth state of many types of cells. Accordingly, cells that lose the ability to respond to TGF-xcex2 are more likely to exhibit uncontrolled growth and to become tumorigenic. Indeed, the cells lack certain tumors such as retinoblastomas lack detectable TGF-xcex2 receptors at their cell surface and fail to respond to TGF-xcex2, while their normal counterparts express self-surface receptors in their growth is potently inhibited by TGF-xcex2 (Kim Chi, A. et al., Science, 240:196-198 (1988)).
More specifically, TGF-xcex21 stimulates the anchorage-independent growth of normal rat kidney fibroblasts (Robert et al., PNAS USA, 78:5339-5343 (1981)). Since then it has been shown to be a multi-functional regulator of cell growth and differentiation (Sporn et al., Science, 233:532-534 (1986)) being capable of such diverse effects of inhibiting the growth of several human cancer cell lines (Roberts et al., PNAS-USA, 82:119-123 (1985)), mouse keratinocytes, (Coffey et al., Cancer RES., 48:1596-1602 (1988)), and T and B lymphocytes (Kehrl et al., J.Exp.Med., 163:1037-1050 (1986)). It also inhibits early hematopoietic progenitor cell proliferation (Goey et al., J.Immunol., 143:877-880 (1989)), stimulates the induction of differentiation of rat, muscle mesenchymal cells and subsequent production of cartilage-specific macro molecules (Seyedine et al., J.Biol.Chem., 262:1946-1949 (1986)), causes increased synthesis and secretion of collagen (Ignotz et al., J.Biol.Chem., 261:4337-4345 (1986)), stimulates bone formation (Noda et al., Endocrinology, 124;2991-2995 (1989)), and accelerates the healing of incision wounds (Mustoe et al., Science, 237:1333-1335 (1987)).
Further, TGF-xcex21 stimulates formation of extracellular matrix molecules in the liver and lung. When levels of TGF-xcex21 are higher than normal, formation of fiber occurs in the extracellular matrix of the liver and lung which can be fatal. High levels of TGF-xcex21 occur due to chemotherapy and bone marrow transplant as an attempt to treat cancers, eg. breast cancer.
A second protein termed TGF-xcex22 was isolated from several sources including demineralized bone, a human prostatic adenocarcinoma cell line (Ikeda et al., Bio.Chem., 26:2406-2410 (1987)). TGF-xcex22 shared several functional similarities with TGF-xcex21. These proteins are now known to be members of a family of related growth modulatory proteins including TGF-xcex23 (Ten-Dijke et al., PNAS-USA, 85:471-4719 (1988)), Muellerian inhibitory substance and the inhibins. Due to amino acid sequence homology, it is thought that the PGF polypeptide of the present invention is also a member of this family of related growth modulatory proteins. However, to date, this polypeptide has only been found by the inventors to be present in the prostate.
In accordance with one aspect of the present inventions there is provided a novel mature polypeptide which is PGF, as well as biologically active and diagnostically or therapeutically useful fragments, analogs and derivatives thereof. The polypeptide of the present invention is of human origin.
In accordance with another aspect of the present invention, there are provided isolated nucleic acid molecules encoding human PGF, including mRNAs, DNAS, cDNAs, genomic DNAs as well as analogs and biologically active and diagnostically or therapeutically useful fragments and derivatives thereof.
In accordance with yet a further aspect of the present invention, there is provided a process for producing such polypeptide by recombinant techniques comprising culturing recombinant prokaryotic and/or eukaryotic host cells, containing a human PGF nucleic acid sequence, under conditions promoting expression of said protein and subsequent recovery of said protein.
In accordance with yet a further aspect of the present invention, there is provided a process for utilizing such polypeptide, or polynucleotide encoding such polypeptide for therapeutic purposes, for example, to inhibit prostate cancer, stimulate tissue regeneration and to promote wound healing.
In accordance with yet a further aspect of the present invention, there are provided antibodies against such polypeptides.
In accordance with yet another aspect of the present invention, there are provided antagonists to such polypeptides, which may be used to inhibit the action of such polypeptides, for example, in the treatment of PGF-dependent tumors.
In accordance with yet a further aspect of the present invention, there are also provided nucleic acid probes comprising nucleic acid molecules of sufficient length to specifically hybridize to human PGF sequences.
In accordance with still another aspect of the present invention, there are provided diagnostic assays for detecting diseases related to the under-expression and over-expression of the PGF polypeptide and mutations in the nucleic acid sequences encoding such polypeptide.
In accordance with yet a further aspect of the present invention, there is provided a process for utilizing such polypeptides, or polynucleotides encoding such polypeptides, for in vitro purposes related to scientific research, synthesis of DNA and manufacture of DNA vectors.
These and other aspects of the present invention should be apparent to those skilled in the art from the teachings herein.